Liquid crystal display device with a built-in touch panel

ABSTRACT

The presence or absence of touch is detected according to a difference of a capacitance caused by the presence or absence of a material that blocks the electric field formed between the detection electrode and the common electrode. The common electrode includes a plurality of divided electrode portions that is extended in a lateral direction and aligned with each other in a longitudinal direction. Each of the plurality of common lines is electrically connected to at least one of the divided electrode portions. The plurality of common lines is arranged in an area next to the common electrode in the lateral direction of the common electrode, arranged next to each other in a width direction orthogonal to a length thereof, is different in width from each other, and the width of the common lines is wider as the length is longer.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/851,184, filed on Mar. 27, 2013, which claims the priority ofJapanese Patent Application No. 2012-104370 filed on May 1, 2012, thecontents of which are hereby incorporated by reference into thisapplication.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device with abuilt-in touch panel.

2. Description of the Related Art

In diffusion of mobile devices, a touch panel technique for supporting agraphical user interface is important. As a touch panel of a capacitivecoupling type has been known as the touch panel technique. In thegeneral touch panel of the capacitive coupling type, a touch panelsubstrate in which a surface of a glass substrate is subjected toconductive coating (transparent conductive film) is provided, andtouched with a finger to implement position detection. Also, a liquidcrystal display panel with a touch panel has been known in which thetouch panel substrate is fitted to the liquid crystal display panel, anda menu screen displayed on the liquid crystal display panel is touchedwith the finger to implement operation according to a menu (refer to JP2006-146895 A).

In the display panel with the touch panel, the touch panel is put on adisplay area surface of the display panel on which information on imagesor characters is displayed in use. In the related-art display panel withthe touch panel, the touch panel and the display panel are manufactured,separately, and put on each other in combination as a final product. Forthat reason, in the related-art display panel with the touch panel,because there is a need to stack the touch panel and the display panelwhich are manufactured, separately, on each other, there arise suchproblems that the display panel with the touch panel is thickened, and acountermeasure against misalignment of stacking is necessary.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a liquid crystaldisplay device with a built-in touch panel in which the touch panel isincorporated into the display device to enable the display device to bethinned as compared with the related art one, and to require nocountermeasure against the misalignment of stacking.

(1) According to the present invention, there is provided a liquidcrystal display device with a built-in touch panel, including: a liquidcrystal material; a first substrate and a second substrate between whichthe liquid crystal display material is held; pixel electrodes formedbetween the first substrate and the second substrate; a common electrodeformed between the first substrate and the second substrate; a detectionelectrode formed on the first substrate; and a plurality of common linesformed on the second substrate so as to be electrically connected to thecommon electrode, in which the liquid crystal material is driven by anelectric field formed between the pixel electrodes and the commonelectrode, in which the presence or absence of touch is detectedaccording to a difference of a capacitance caused by the presence orabsence of a material that blocks the electric field formed between thedetection electrode and the common electrode, in which the commonelectrode includes a plurality of divided electrode portions that isextended in a lateral direction and aligned with each other in alongitudinal direction, in which each of the plurality of common linesis electrically connected to at least one of the divided electrodeportions, in which the plurality of common lines is arranged in an areanext to the common electrode in the lateral direction of the commonelectrode, arranged next to each other in a width direction orthogonalto a length thereof, is different in width from each other, and thewidth of the common lines is wider as the length is longer. According tothe present invention, the touch panel is configured by the firstsubstrate, the detection electrode, and the common electrode, and thetouch panel is incorporated into the liquid crystal display device. As aresult, the device can be thinned more than the related-art one, and nocountermeasure against the misalignment of stacking those components oneach other is required. Also, since the plurality of common lines isformed so that the width is wider as the length is longer, a differencein the resistance value caused by a difference of the lengths can bereduced.

(2) In the liquid crystal display device with a built-in touch panelaccording to the item (1), each of the plurality of common lines has oneend thereof in the area next to the common electrode in the lateraldirection, and extends from the one end in an extension direction whichis one of the vertical directions, and one ends of the plurality ofcommon lines are positionally displaced in the extension direction inthe order from the longest common line to the shortest common line.

(3) In the liquid crystal display device with a built-in touch panelaccording to the item (2), the shortest common line is arranged at aside closest to the common electrode in the lateral direction, and thelongest common line is arranged at a side farthest from the commonelectrode in the lateral direction, and the plurality of common lines ismore distant from the common electrode in the lateral direction as thelength of the common lines is longer.

(4) In the liquid crystal display device with a built-in touch panelaccording to the item (3), except for at least the shortest common line,the respective common lines 58 each have a plurality of portionsdifferent in width along the length direction, the number of theplurality of common lines is n, and in a longitudinal side area that isadjacent to the one end of an m (1≦m)^(th) common line from the shortestcommon line on an upper side in the extension direction, and extends ina width direction, (m+1)^(th) to n^(th) common lines are arranged inparallel, and in a lateral side area that is adjacent to the one end ofthe m (1≦m)^(th) common line from the shortest common line in thelateral direction, the (m+1)^(th) to n^(th) common lines are arranged inparallel. The longitudinal side area is wider in the lateral directionthan the lateral side area, and in the (m+1)^(th) to n^(th) commonlines, the width of a portion situated in the vertical side area iswider than the width of a portion situated in the lateral side area.

(5) In the liquid crystal display device with a built-in touch panelaccording to the item (4), a difference of the width in the lateraldirection between the longitudinal side area and the lateral side areais equal to a width of the one end of the m^(th) common line in thelateral direction.

(6) In the liquid crystal display device with a built-in touch panelaccording to the item (5), a difference between a total of the widths ofthe portions of the (m+1)^(th) to n^(th) common lines provided in thelongitudinal side area, and a total of the widths of the portions of the(m+1)^(th) to n^(th) common lines provided in the lateral side area isequal to the width of the one end of the m^(th) common line in thelateral direction.

(7) In the liquid crystal display device with a built-in touch panelaccording to any one of the items (1) to (6), each of the plurality ofcommon lines is electrically connected to two or more of the dividedelectrode portions.

(8) In the liquid crystal display device with a built-in touch panelaccording to any one of the items (1) to (6), each of the plurality ofcommon lines is electrically connected to one of the divided electrodeportions.

(9) In the liquid crystal display device with a built-in touch panelaccording to any one of the items (1) to (8), each of the plurality ofcommon lines is electrically connected to the at least one of thedivided electrode portions by at least one connection portion.

(10) In the liquid crystal display device with a built-in touch panelaccording to the item (9), the number of the at least one connectionportion is larger as the length of the one common line electricallyconnected thereto is larger.

(11) In the liquid crystal display device with a built-in touch panelaccording to the item (9) or (10), a length of the at least oneconnection portion is longer as the length of the one common lineelectrically connected thereto is shorter.

(12) In the liquid crystal display device with a built-in touch panelaccording to any one of the items (9) to (11), the at least oneconnection portion is thinner as the length of the one common lineelectrically connected thereto is shorter.

(13) In the liquid crystal display device with a built-in touch panelaccording to any one of the items (1) to (12), the second substratefurther includes a circuit, and the plurality of common lines is formedto overlap with the circuit.

(14) In the liquid crystal display device with a built-in touch panelaccording to anyone of the items (1) to (13), the pixel electrodes andthe common electrode are formed on the second substrate, and theelectric field formed between the pixel electrodes and the commonelectrode is a lateral electric field.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a liquid crystal display device witha built-in touch panel according to an embodiment of the presentinvention;

FIG. 2 is an exploded perspective view of a main portion of the liquidcrystal display device with a built-in touch panel according to theembodiment of the present invention;

FIG. 3 is a perspective view illustrating the details of a secondsubstrate;

FIG. 4 is a diagram illustrating a circuit for displaying an image on aliquid crystal display panel;

FIG. 5 is a diagram illustrating the details of a common electrode andcommon lines;

FIG. 6 is a cross-sectional view of the common lines taken along a lineVI-VI in FIG. 5;

FIG. 7 is a diagram illustrating a modified example 1 in the embodimentof the present invention;

FIG. 8 is a diagram illustrating a modified example 2 in the embodimentof the present invention;

FIG. 9 is a diagram illustrating a modified example 3 in the embodimentof the present invention;

FIG. 10 is a diagram illustrating a modified example 4 in the embodimentof the present invention;

FIG. 11 is a diagram illustrating a modified example 5 in the embodimentof the present invention;

FIG. 12 is a cross-sectional view of the common lines taken along a lineVII-VII in FIG. 11;

FIG. 13 is a diagram illustrating a structure in which an exampleillustrated in FIG. 12 is further modified; and

FIG. 14 is a diagram illustrating a resistance value of the commonlines.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a cross-sectional view of a liquid crystal display device witha built-in touch panel according to an embodiment of the presentinvention. The liquid crystal display device with the built-in touchpanel includes a first substrate 10 and a second substrate 12. A liquidcrystal material 14 is disposed between the first substrate 10 and thesecond substrate 12. Oriented films 16 are formed between the firstsubstrate 10 and the second substrate 12 to sandwich the liquid crystalmaterial 14 therebetween.

The first substrate 10 is made of a light transmissive material (forexample, glass). The first substrate 10 is formed of a color filtersubstrate on which a colored layer and a black matrix not shown in thedrawing are formed. On the first substrate 10 is formed the orientedfilm 16. The oriented film 16 is formed on the colored layer and theblack matrix not shown in the drawing.

The second substrate 12 is made of a light transmissive material (forexample, glass). On the second substrate 12 is formed thin filmtransistors 18, and therefore the second substrate 12 is also called“TFT substrate”. Each of the thin film transistors 18 includes asemiconductor film 20 made of polysilicon or the like, a gate insulatingfilm 22 that covers the semiconductor film 20, gate electrodes 24arranged above the semiconductor film 20 through the gate insulatingfilm 22, and a source electrode 26 and a drain electrode 28 which areelectrically connected to the semiconductor film 20 through the gateinsulating film 22.

One of the source electrode 26 and the drain electrode 28 iselectrically connected to the pixel electrodes 30. Also, a commonelectrode 34 is formed in a layer position different from that of pixelelectrodes 30 through an insulating film 32. In an example of FIG. 1,the pixel electrodes 30 are located above the common electrode 34 (aside distant from the second substrate 12), but those electrodes may bearranged upside down.

The above components configure a liquid crystal display panel 36, andthe liquid crystal material 14 is driven by an electric field developedbetween the pixel electrodes 30 and the common electrode 34. Since thepixel electrodes 30 and the common electrode 34 are formed over thesecond substrate 12, the electric field developed between the pixelelectrodes 30 and the common electrode 34 is a lateral electric field.Alternatively, the pixel electrodes 30 may be formed over the secondsubstrate 12, the common electrode 34 may be formed over the firstsubstrate 10, and the liquid crystal material 14 may be driven by alongitudinal electric field. In any configurations, the pixel electrodes30 and the common electrode 34 may be arranged between the firstsubstrate 10 and the second substrate 12.

The liquid crystal display device with a built-in touch panel has adetection electrode 38 formed on the first substrate 10. In the exampleof FIG. 1, the detection electrode 38 is arranged on a surface of thefirst substrate 10 opposite to the liquid crystal material 14. Therespective different voltages are applied to the detection electrode 38and the common electrode 34 to form an electric field (fringe electricfield) therebetween (in detail, outside of an opposed area). Thepresence or absence of touch is detected according to a difference inthe capacitance depending on the presence or absence of a material (forexample, a finger 40) that blocks the electric field developed betweenthe detection electrode 38 and the common electrode 34. That is, a touchpanel 42 is configured by the first substrate 10, the detectionelectrode 38 and the common electrode 34. A front panel 46 is attachedto the touch panel 42 through an adhesive layer 44 for reinforcement.According to this embodiment, since the touch panel 42 is incorporatedinto the liquid crystal display device, the device can be thinned morethan the related-art one. Also, since the liquid crystal display panel36 and the touch panel 42 share the first substrate 10, nocountermeasure against the misalignment of stacking those components oneach other is required.

FIG. 2 is an exploded perspective view of a main portion of the liquidcrystal display device with the built-in touch panel according to theembodiment of the present invention. The first substrate 10 has arectangular planar shape, and a plurality of the detection electrodes 38extends in a longitudinal direction along a long side thereof. The firstsubstrate 10 is fitted with a flexible wiring substrate 48 for electricconnection between the detection electrode 38 and the external portion.An integrated circuit chip 50 incorporating a liquid crystal drivercircuit is mounted on the second substrate 12, and a flexible wiringsubstrate 52 is fitted to the second substrate 12 for electricconnection with the external.

FIG. 3 is a perspective view illustrating the details of the secondsubstrate 12. The common electrode 34 includes a plurality of dividedelectrode portions 54 extending in a lateral direction and aligned witheach other in the longitudinal direction. The second substrate 12 has arectangular planar shape, and the plurality of divided electrodeportions 54 extends in the lateral direction along the short side. Thedirection along which the plurality of divided electrode portions 54extends intersects with (for example, is orthogonal to) the directionalong which the plurality of detection electrode 38 (FIG. 2) extends.

FIG. 4 is a diagram illustrating a circuit for displaying an image onthe liquid crystal display panel 36. The pixel electrodes 30 are formedin an image display area 56. Since pixels are formed by the plurality ofpixel electrodes 30, an area surrounding the plurality of pixelelectrodes 30 represents the image display area 56. In the image displayarea 56 is formed the common electrode 34 including the plurality ofdivided electrode portions 54. The potential of the divided electrodeportions 54 is set to a reference potential (for example, GND), and avoltage corresponding to the brightness of each pixel is applied to thepixel electrode 30. An image is displayed under the control (forexample, drive of the liquid crystal material 14) of the light using theelectric field developed between the pixel electrodes 30 and the commonelectrode 34.

The common electrode 34 is electrically connected to common lines 58,and the pixel electrodes 30 are electrically connected to signal lines60. A switching element 62 (for example, the thin film transistor 18illustrated in FIG. 1) is connected between each of the pixel electrodes30 and each of the signal lines 60 to conduct electric continuity ordiscontinuity between the pixel electrode 30 and the signal line 60.Each switching element 62 is connected to a scanning line 64 drawn outof a scanning circuit not shown, and driven (turned on/off) according toa scanning signal input to the scanning line 64.

FIG. 5 is a diagram illustrating the details of the common electrode 34and the common lines 58. FIG. 6 is a cross-sectional view of the commonlines 58 taken along a line VI-VI in FIG. 5.

The common electrode 34 is made of a transparent conductive materialsuch as ITO (indium tin oxide). The common electrode 34 includes theplurality of divided electrode portions 54, and two or more (six in FIG.5) divided electrode portions 54 are electrically connected to eachother. The common electrode 34 includes a connection portion 66 drawnout of the divided electrode portions 54. The connection portion 66 ismade of the same material as the divided electrode portions 54, andcontinuously integrated therewith.

The plurality of common lines 58 made of, for example, metal, is formedon the second substrate 12. As illustrated in FIG. 6, a first inorganicpassivation film 68 and an organic passivation film 70 are laminated onthe common lines 58 in the stated order. Each connection portion 66integrated with the divided electrode portions 54 is arranged on theorganic passivation film 70. A second inorganic passivation film 72 isso formed as to cover the connection portion 66 and the organicpassivation film 70.

The first inorganic passivation film 68 has an opening 78 to which eachcommon line 58 is exposed. The organic passivation film 70 has athrough-hole 74 larger than the opening 78 so as to be communicated withthe opening 78. The second inorganic passivation film 72 is also formedon an inner surface of the through-hole 74 of the organic passivationfilm 70, but does not stop the opening 78 of the first inorganicpassivation film 68. The second inorganic passivation film 72 has anopening 76 to which the connection portion 66 is exposed.

A conductive film 80 is formed on the second inorganic passivation film72. The conductive film 80 extends to an inside of the opening 76, andestablishes an electric continuity with the connection portion 66. Theconductive film 80 extends to an inside of the opening 78, andestablishes an electric continuity with the common lines 58. Theconductive film 80 extends continuously from the inside of the opening76 to the inside of the opening 78. The conductive film 80 is made ofthe same material (for example, ITO (indium tin oxide) as that of thepixel electrodes 30 (refer to FIG. 1), and formed together with thepixel electrodes 30. The common lines 58 and the connection portion 66are electrically connected to each other by the conductive film 80. Thecommon lines 58 are electrically connected to the common electrode 34(refer to FIG. 5).

As illustrated in FIG. 5, each of the plurality of common lines 58 iselectrically connected to at least one (for example, two or more) of thedivided electrode portions 54. Each of the plurality of common lines 58and at least one (six in FIG. 5) of the divided electrode portions 54are electrically connected to each other by at least one (one in FIG. 5)connection portion 66.

The plurality of common lines 58 is arranged in an area next to thecommon electrode 34 in a direction (lateral direction) along which thecommon electrode 34 extends. The plurality of common lines 58 isarranged next to each other in a width direction orthogonal to a lengththereof. As illustrated in FIG. 3, the shortest common line 58 a isarranged at aside closest to the common electrode 34 in the lateraldirection. Also, the longest common line 58 b is arranged at a sidefarthest from the common electrode 34 in the lateral direction. Theplurality of common lines 58 is more distant from the common electrode34 in the lateral direction as the length of the common lines 58 islonger (refer to FIG. 3).

As illustrated in FIG. 5, the plurality of common lines 58 each has oneend thereof in the area next to the common electrode 34 in the lateraldirection (right side in FIG. 5). Each of the common lines 58 extendsfrom the one end in an extension direction (downward in FIG. 5) which isone of the vertical directions. As illustrated in FIG. 3, one ends ofthe plurality of common lines 58 are positionally displaced in theextension direction (downward in FIG. 5) in the order from the longestcommon line 58 b to the shortest common line 58 a.

As illustrated in FIG. 5, in a longitudinal side area RL that isadjacent to one end of an m (1≦m)^(th) common line 58 from the shortestcommon line 58 on an upper side in the extension direction, and extendsin a width direction, (m+1)^(th) to n^(th) (n is the number of commonlines 58) common lines 58 are arranged in parallel. For instance, in anexample of m=1, in a longitudinal side area RL₁ that is adjacent to oneend of a first common line 58 from the shortest common line 58 on theupper side in the extension direction, and extends in the widthdirection, second to n^(th) (n is the number of common lines 58) commonlines 58 are arranged in parallel. In an example of m=2, in alongitudinal side area RL₇ that is adjacent to one end of the secondcommon line 58 from the shortest common line 58 on the upper side in theextension direction, and extends in the width direction, third to n^(th)(n is the number of common lines 58) common lines 58 are arranged inparallel.

In a lateral side area RW that is adjacent to one end of the m(1≦m)^(th) common line 58 from the shortest common line 58 in thelateral direction, the (m+1)^(th) to n^(th) common lines 58 are arrangedin parallel. For example, in an example of m=1, in a lateral side areaRW₁ that is adjacent to one end of a first common line 58 from theshortest common line 58 in the lateral direction, the second to n^(th)common lines 58 are arranged in parallel. In an example of m=2, in alateral side area RW₂ that is adjacent to one end of the second commonline 58 from the shortest common line 58 in the lateral direction, thethird to n^(th) common lines 58 are arranged in parallel.

The longitudinal side area RL is wider than the lateral side area RW inthe lateral direction. A difference of the width in the lateraldirection between the longitudinal side area RL and the lateral sidearea RW which are located next to the m^(th) common line 58 is equal toa width of one end of the m^(th) common line 58 in the lateraldirection. For example, a difference of the width in the lateraldirection between the longitudinal side area RI, and the lateral sidearea RW₁ which are located next to the first common line 58 is equal toa width W₁ of one end of the first common line 58 in the lateraldirection.

The plurality of common lines 58 is different in width from each other,and formed so that the width of the common lines 58 is wider as thelength thereof is longer. In an example illustrated in FIG. 5, arelationship of W₁<W₂< . . . <W_(n) is satisfied.

Except for at least the shortest common line 58, the respective commonlines 58 each have a plurality of portions different in width along thelength direction. The shortest common line 58 may have a plurality ofportions different in width in the length direction, or may not havesuch portions.

In each of the (m+1)^(th) to n^(th) common lines 58, the width of aportion situated in the longitudinal side area RL located next to them^(th) common line 58 is wider than the width of a portion situated inthe lateral side area RW located next to the m^(th) common line 58.

For instance, in an example of m=1, in the second common line 58, awidth W₂₂ of a portion situated in the longitudinal side area RL₁located next to the first common line 58 is wider than a width W₂ of aportion situated in the lateral side area RW₁ located next to the firstcommon line 58. Also, in the third common line 58, a width W₃₂ of aportion situated in the longitudinal side area RL₁ located next to thefirst common line 58 is wider than a width W₃ of a portion situated inthe lateral side area RW₁ located next to the first common line 58. Inthe n^(th) common line 58, a width W_(n2) of a portion situated in thelongitudinal side area RL₁ located next to the first common line 58 iswider than a width W_(n) of a portion situated in the lateral side areaRW₁ located next to the first common line 58.

In an example of m=2, in the third common line 58, a width W₃₃ of aportion situated in the longitudinal side area RL₂ located next to thesecond common line 58 is wider than a width W₃₂ of a portion situated inthe lateral side area RW₂ located next to the second common line 58.

In the example of FIG. 5, the following expressions are satisfied.W ₂ <W ₂₂ ,W ₃ <W ₃₂ <W ₃₃ , . . . ,W _(n) <W _(n2) . . . <W _(nn)

A difference between a total of the widths of portions of the (m+1)^(th)to n^(th) common lines 58 provided in the longitudinal side area RLlocated next to the m^(th) common line 58, and a total of the widths ofportions of the (m+1)^(th) to n^(th) common lines 58 provided in thelateral side area RW located next to the m^(th) common line 58 is equalto the width of one end of the m^(th) common line 58 in the lateraldirection.

For instance, in an example of m=1, in the second to n^(th) common lines58, a difference between a total of the widths W₂₂, W₃₂, . . . , W_(n2)of portions provided in the longitudinal side area RL₁ located next tothe first common line 58, and a total of the widths W₂, W₃, . . . ,W_(n) of portions provided in the lateral side area RW₁ located next tothe first common line 58 is equal to the width W₁ of one end of thefirst common line 58 in the lateral direction. That is, the followingexpression is satisfied.(W ₂₂ −W ₂)+(W ₃₂ −W ₃)+ . . . +(W _(n2) −W _(n))=W ₁

According to this embodiment, since the plurality of common lines 58 isformed so that the width of the common lines 58 is wider as the lengththereof is longer, a difference in a resistance value due to adifference in the length can be reduced.

Modified Example

FIG. 7 is a diagram illustrating a modified example 1 in the embodimentof the present invention. In this example, an inorganic passivation film182 is formed on a common line 158 as an example of the inorganic film.The inorganic passivation film 182 has a through-hole 184 to which thecommon line 158 is exposed. A connection portion 166 that is a part ofthe common electrode is formed on the inorganic passivation film 182 soas to establish an electric continuity with the common line 158 throughthe through-hole 184. The common line 158 is electrically connected tothe common electrode by the connection portion 166. This example is amodified example of the structure illustrated in FIG. 6, and the detailsof the other configurations correspond to those described in the aboveembodiment.

FIG. 8 is a diagram illustrating a modified example 2 in the embodimentof the present invention. In this example, connection portions 266 arethinner as the lengths of common lines 258 electrically connectedthereto are shorter. As described in the above embodiment, the commonlines 258 are shorter as the common lines 258 are closer to a commonelectrode 234. A connection portion 266 a connected to a common line 258a closest to the common electrode 234 is thinnest. The connectionportions 266 are thinner as the common lines 258 electrically connectedthereto is closer to the common electrode 234. When the connectionportions 266 are thinned, resistance values thereof can be increased.Since the resistance value of the common lines 258 is lower as thelength of the common lines 258 is shorter, the connection portion 266 aof a high resistance is connected to the common line 258 a of a lowresistance so that a difference from the resistance values between theother common lines 258 and divided electrode portions 254 can bereduced.

Also, the length of the connection portions 266 is longer as the lengthof the common lines 258 electrically connected thereto is shorter. Theconnection portions 266 become lengthened with a bent shape. The lengthof the connection portions 266 can be changed by changing the bentshape. When the connection portions 266 are lengthened, the resistancevalue thereof can be increased. Since the resistance value is lower asthe length of the common lines 258 is shorter, the connection portion266 a of the high resistance is connected to the common line 258 a ofthe low resistance so that a difference from resistance values betweenthe other common lines 258 and divided electrode portions 254 can bereduced. The details of the other configurations correspond to thosedescribed in the above embodiment.

FIG. 9 is a diagram illustrating a modified example 3 in the embodimentof the present invention. In this example, each of a plurality of commonlines 358 is electrically connected to one divided electrode portion354. Alternatively, the divided electrode portions 354 illustrated inFIG. 9 are wider in width than the divided electrode portions 54illustrated in FIG. 5. Also, one divided electrode portion 354illustrated in FIG. 9 is shaped to integrate the plurality of dividedelectrode portions 54 illustrated in FIG. 5 together. The details of theother configurations correspond to those described in the aboveembodiment.

FIG. 10 is a diagram illustrating a modified example 4 in the embodimentof the present invention. In this example, the number of connectionportions 466 connected to each common line 458 is larger as the lengthof the common line 458 is longer. The number of connection portions 466a connected to the common line 458 a closest to the common electrode 434is smallest. The resistance value of the connection portions can bedecreased with the increased number of connection portions 466. Sincethe resistance value of the common line 458 is higher as the common line458 is longer, a plurality of connection portions 466 b low in acombined resistance value is connected to a common line 458 b high inresistance so that a difference from the resistance value between thecommon line 458 a and divided electrode portions 454 a can be reduced.The details of the other configurations correspond to those described inthe above embodiment.

FIG. 11 is a diagram illustrating a modified example 5 in the embodimentof the present invention. FIG. 12 is a cross-sectional view of thecommon lines taken along a line XII-XII in FIG. 11. In this example, asecond substrate 512 has circuit 586 such as a scanning circuit. Thecircuit 586 is configured by a film laminated on the second substrate512. For example, as illustrated in FIG. 12, semiconductor films 520made of polysilicon or the like are formed on the second substrate 512,and first metal films 590 are formed above the semiconductor films 520through an insulating film 588. The first metal films 590 configure gateelectrodes at position not shown, and a thin film transistor isconfigured by those laminated films. The circuit 586 includes an activeelement such as a thin film transistor.

A plurality of common lines 558 is formed to overlap with the circuit586. For example, an interlayer insulating film 592 is formed on thefirst metal films 590 configuring the gate electrodes. On the interlayerinsulating film 592 is formed a second metal film 594 for configuringthe common lines 558. A first inorganic passivation film 568 and anorganic passivation film 570 are laminated on the second metal film 594in the stated order. A transparent conductive film 580 for configuringthe common electrode is formed on the organic passivation film 570, anda second inorganic passivation film 572 is formed on the transparentconductive film 580. The transparent conductive film 580 is made of ITO(indium tin oxide). The details of the other configurations correspondto those described in the above embodiment.

FIG. 13 is a diagram illustrating a structure in which the exampleillustrated in FIG. 12 is further modified. In this example, a metalfilm 596 is formed in contact with a lower surface of the transparentconductive film 580. The metal film 596 is formed at a positionoverlapping with the circuit 586 such as the scanning circuit withavoiding an image display area 556 (refer to FIG. 11). A part (forexample, connecting portion) of the common electrode 534 configured bythe transparent conductive film 580 is located outside of the imagedisplay area 556, and the metal film 596 overlaps with that part(connection portion, etc.) to reduce the resistance values between thecommon lines 558 and the divided electrode portions 554.

Example

FIG. 14 is a diagram illustrating a resistance value of the commonlines. An end of an m^(th) common line 658 _(m), and an end of an(m−1)^(th) common line 658 _(m-1) from the common line closest to thecommon electrode not shown are illustrated. The resistance value of thecommon lines will be described in an example of a first area A₁ having alength of D₁ to the end of the (m−1)^(th) common line 658 _(m-1), and asecond area A₂ adjacent to the first area A₁ and having a length of D₂to the end of the m^(th) common line 658 _(m).

It is assumed that a width of the m^(th) common line 658 _(m) in thefirst area A₁ is W_(1A), and a width of the m^(th) common line 658 _(m)in the second area A₂ is W_(1B). In the example illustrated in FIG. 14,the second area A₂ has a portion smaller in the width than the widthW_(1B), but an increase in the resistance value caused by that portioncan be ignored. It is assumed that a width of the (m−1)^(th) common line658 _(m-1) in the first area A₁ is W₂. The common lines 658 _(m) and 658_(m-1) are made of metal having the same thickness, and their sheetresistances are each R_(metal).

The common lines 658 _(m) and 658 _(m-1) are connected with connectionportions 666 _(m) and 666 _(m-1) which are parts of the commonelectrode, respectively. It is assumed that the connection portions 666_(m) and 666 _(m-1) are made of ITO (indium tin oxide), and their widthsW_(ito1) and W_(ito2) are identical with each other. Also, theconnection portions 666 _(m) and 666 _(m-1) are different in length fromeach other due to a positional displacement of the common lines 658 _(m)and 658 _(m-1). However, it is assumed that a resistance value of aportion of a difference W_(min) in the length therebetween can beignored, and lengths D₁ and D₂ of the first area A₁ and the second areaA₂ are each equal to a length D. That is,W _(min)≈0D ₁ =D ₂ =D

Under the above conditions, the resistance value R_(m) of the m^(th)common line 658 _(m) is represented as follows.R _(m)={(D×R _(metal))/W _(1A)}+{(D×R _(metal))/W _(1B)}The resistance value R_(m-1) of the (m−1)^(th) common line 658 _(m-1) isrepresented as follows.R _(m-1)={(D×R _(metal))/W ₂}

In this example, as compared with a case in which the m^(th) common line658 _(m) is formed in the second area A₂ with the same width as thewidth W_(1A) in the first area A₁, a resistance value R_(decrease)decreased by enlarging the width of the m^(th) common line 658 _(m) inthe second area A₂ is represented as follows.R _(decrease)=[{(D×R _(metal))/W _(1A)}+{(D×R _(metal))/W _(1A)}]−[{(D×R_(metal))/W _(1A)}+{(D×R _(metal))/W _(1B)}]={(D×R _(metal))/W_(1A)}−{(D×R _(metal))/W _(1B) }=D×R _(metal)×(1/W _(1A)−1/W _(1B))=D×R_(metal)×{(W _(1B) −W _(1A))/W _(1A) ×W _(1B)}  (1)

If the width of the m^(th) common line 658 is enlarged in the secondarea A₂ by the amount corresponding to the width W₂ of the common line658 _(m-1) which is not present in the second area A₂, the followingexpression is satisfied.W _(1B) −W _(1A) ≈W2Therefore, this value is assigned to Expression (1) to obtain thefollowing expression.R _(decrease) =D1×R _(metal) ×{W2/(W _(1A) ×W _(1B))}

With use of the above relationship, the first area A₁ or the second areaA₂, or the areas to the terminals (portions where a flexible wiringsubstrate not shown is connected) of the common line 658 _(m) and 658_(m-1) can be designed so that the resistance values of the adjacentcommon lines 658 _(m) and 658 _(m-1) become equal to each other.

While there have been described what are at present considered to becertain embodiments of the invention, it will be understood that variousmodifications may be made thereto, and it is intended that the appendedclaims coverall such modifications as fall within the true spirit andscope of the invention.

What is claimed is:
 1. A liquid crystal display device with a built-intouch panel, comprising: a first substrate and a second substrate; aliquid crystal material held between the first substrate and the secondsubstrate; a plurality of pixel electrodes formed above the secondsubstrate; a common electrode formed above the second substrate; adetection electrode formed above the first substrate; and a plurality ofcommon lines formed above the second substrate so as to be electricallyconnected to the common electrode, wherein the liquid crystal materialis driven by an electric field formed between the pixel electrodes andthe common electrode which is applied a reference voltage, wherein thepresence or absence of touch is detected according to a difference of acapacitance between the detection electrode and the common electrodewhich is applied a detection voltage, wherein the common electrodeincludes a plurality of divided electrodes extending in a lateraldirection and aligned with each other in a longitudinal direction,wherein the plurality of common lines is arranged in an area next to thecommon electrode in the lateral direction of the common electrode,wherein the plurality of common lines has parallel arranged portions inthe area next to the common electrode, each of the plurality of commonlines having an end portion, wherein an insulation layer is formedbetween the common lines and the divided electrodes, the insulationlayer having a connecting opening formed above the end portion of eachof the plurality of common lines, wherein a conductive film, which isformed in the connecting opening, electrically connects between each ofthe plurality of common lines and some of the plurality of dividedelectrodes, wherein each of the plurality of common lines has the endportion in a greater width in the lateral direction than a correspondingone of the parallel arranged portions in a width in the lateraldirection and wherein the end portion of a longer one of the pluralityof common lines is wider in the lateral direction than the end portionof a shorter one of the plurality of common lines.
 2. The liquid crystaldisplay device with a built-in touch panel according to claim 1, whereineach of the plurality of common lines has the end portion in the areanext to the common electrode in the lateral direction, and extends fromthe end portion in the extension direction which is one of the verticaldirections, and the end portions of the plurality of common lines arepositionally displaced in the extension direction in the order from thelongest common line to the shortest common line.
 3. The liquid crystaldisplay device with a built-in touch panel according to claim 2, whereinthe shortest common line is arranged at a side closest to the commonelectrode in the lateral direction, wherein the longest common line isarranged at a side farthest from the common electrode in the lateraldirection, and wherein the plurality of common lines is more distantfrom the common electrode in the lateral direction as the common linesis longer.
 4. The liquid crystal display device with a built-in touchpanel according to claim 3, wherein except for at least the shortestcommon line, the respective common lines each have a plurality ofportions different in width along the extension direction, wherein thenumber of the plurality of common lines is n, wherein in a longitudinalside area that is adjacent to the end portion of an m (1≦m)^(th) commonline from the shortest common line on an upper side in the extensiondirection, and extends in a width direction, (m+1)^(th) to n^(th) commonlines are arranged in parallel, wherein in a lateral side area that isadjacent to the end portion of the m (1≦m)^(th) common line from theshortest common line in the lateral direction, the (m+1)^(th) to n^(th)common lines are arranged in parallel, wherein the longitudinal sidearea is wider in the lateral direction than the lateral side area, andwherein in the (m+1)^(th) to n^(th) common lines, the width of a portionsituated in the vertical side area is wider than the width of a portionsituated in the lateral side area.
 5. The liquid crystal display devicewith a built-in touch panel according to claim 4, wherein a differenceof the width in the lateral direction between the longitudinal side areaand the lateral side area is equal to a width of the end portion of them^(th) common line in the lateral direction.
 6. The liquid crystaldisplay device with a built-in touch panel according to claim 5, whereina difference between a total of the widths of the portions of the(m+1)^(th) to n^(th) common lines provided in the longitudinal sidearea, and a total of the widths of the portions of the (m+1)^(th) ton^(th) common lines provided in the lateral side area is equal to thewidth of the end portion of the m^(th) common line in the lateraldirection.
 7. The liquid crystal display device with a built-in touchpanel according to claim 6, wherein the number of the conductive film islarger as the length of the one common line electrically connectedthereto is larger.
 8. The liquid crystal display device with a built-intouch panel according to claim 1, wherein the second substrate furtherincludes a circuit, and wherein the plurality of common lines is formedto overlap with the circuit.
 9. The liquid crystal display device with abuilt-in touch panel according to claim 1, wherein the pixel electrodesand the common electrode are formed on the second substrate, and whereinthe electric field formed between the pixel electrodes and the commonelectrode is a lateral electric field.
 10. A liquid crystal displaydevice with a built-in touch panel, comprising: a liquid crystalmaterial; a first substrate and a second substrate between which theliquid crystal material is held; pixel electrodes formed between thefirst substrate and the second substrate; a common electrode formedbetween the first substrate and the second substrate; a detectionelectrode formed on the first substrate; and a plurality of common linesformed on the second substrate so as to be electrically connected to thecommon electrode, wherein the liquid crystal material is driven by anelectric field formed between the pixel electrodes and the commonelectrode which is applied a reference voltage, wherein the presence orabsence of touch is detected according to a difference of a capacitancebetween the detection electrode and the common electrode which isapplied a detection voltage, wherein the common electrode includes aplurality of divided electrodes extending in a lateral direction andaligned with each other in a longitudinal direction, wherein theplurality of common lines are formed in a side area next to the commonelectrode in the lateral direction and next to each other in a widthdirection orthogonal to an extension direction thereof, wherein theplurality of common lines has parallel arranged portions in the sidearea, each of the plurality of common lines having an end portion,wherein the parallel arranged portions are arranged in parallel to eachother, and different in width from each other, wherein a longer one ofthe plurality of common lines in total length has a corresponding one ofthe parallel arranged portions wider in width than a shorter one of theplurality of common lines, wherein each of the plurality of common lineshas an end portion in parallel to another of the plurality of commonlines at a corresponding one of the parallel arranged portions and nextto the plurality of divided electrodes in the lateral direction, each ofthe plurality of common lines having the end portion nearer than thecorresponding one of the parallel arranged portions, wherein aninsulation layer is formed between the common lines and the dividedelectrodes, the insulation layer having a connecting opening formedabove the end portion of each of the plurality of common lines, whereina conductive film, which is formed in the connecting opening,electrically connects between each of the plurality of common lines andsome of the plurality of divided electrodes, wherein the end portionextends along an arrangement of the plurality of divided electrodes inthe side area, wherein each of the plurality of common lines has the endportion in a greater width in the lateral direction than a correspondingone of the parallel arranged portions in a width in the lateraldirection, and wherein the end portion of a longer one of the pluralityof common lines is wider in the lateral direction than the end portionof a shorter one of the plurality of common lines.
 11. The liquidcrystal display device with a built-in touch panel according to claim10, wherein end portions in the side area of the plurality of commonlines are arranged in the longitudinal direction in the order from thelongest common line to the shortest common line.
 12. The liquid crystaldisplay device with a built-in touch panel according to claim 10 whereinthe shortest common line in the side area is arranged at a side closestto the common electrode in the lateral direction, and wherein thelongest common line in the side area is arranged at a side farthest fromthe common electrode in the lateral direction.
 13. The liquid crystaldisplay device with a built-in touch panel according to claim 10,wherein except for at least the shortest common line, the respectivecommon lines each have the plurality of parallel arranged portionsdifferent in width along the extension direction, wherein the number ofthe plurality of common lines is n, wherein the plurality of commonlines includes mth (1≦m<n) and (m+1)th common line, wherein the mthcommon line has mth end portion, wherein the (m+1)th common line has(m+1)th end portion, wherein (m+1)th to nth parallel arranged portionsare arranged in a lateral side area which is situated in the lateraldirection next to the mth end portion, wherein mth end portion and(m+2)th to nth parallel arrange portions are arranged in a longitudinalside area which is situated in the longitudinal direction next to themth end portion, wherein a total width in the lateral direction of thelongitudinal side area is wider than a total width in the lateraldirection of the lateral side area.
 14. The liquid crystal displaydevice with a built-in touch panel according to claim 10 wherein adifference of the width in the lateral direction between thelongitudinal side area and the lateral side area is equal to a width ofthe end portion of the m^(th) common line in the lateral direction. 15.The liquid crystal display device with a built-in touch panel accordingto claim 13, wherein the width in the lateral direction of the (m+1)thend portion is wider than that of the (m+1)th parallel arranged portionin the lateral side area.